It is well known that fluorocarbons impart surface activity such as water and oil repellency, soil and chemical resistance when applied to a substrate. These unique properties of fluorocarbons which are related to their olephilic and hydrophobic character have drawn considerable attention because a significant effect is produced even when used in low amounts. However, due to the high cost of the fluorocarbons the commercial application has either been limited or the fluorine functionality has been incorporated into polymers.
On the other hand. polyvinyl alcohol is a high surface energy, hydrophilic polymer with excellent physical and mechanical properties. It has been used in such areas as adhesives, emulsions, textiles and in solvent barrier coatings. However, being a water soluble polymer, polyvinyl alcohol has poor water repellency, no oil repellancy and no soil resistance.
Therefore attempts have been made to improve the above properties of polyvinyl alcohol by introducing fluorine functionality onto the backbone to produce a copolymer with low surface energy and improved water and oil repellency.
U.S. Pat. No. 4,574,139 discloses a vinyl ester polymer having a fluorine-containing end group which is produced by polymerizing vinyl ester in the presence of a fluorine-containing thiol. The corresponding vinyl alcohol polymer having a fluorine-containing end group is produced by saponification of the vinyl ester polymer.
U.S. Pat. No. 4,557,955 discloses films and tubular structures which are selectively permeable to liquids and gases and are based on a copolymer composed of copolymerized fluorinated olefin, copolymerized vinyl acetate and, optionally, a copolymerized olefin. At least 50% of the acetate groups of the copolymer may be saponified to form OH groups.
DE 3,415,975 discloses polymers useful as emulsifiers, adhesives and photosensitive layers prepared by polymerizing vinyl esters, fluorine-containing vinyl compounds and, optionally, unsaturated carboxylic acids and/or other comonomers, and optionally saponification of the copolymers.